At least one tornado was spotted Friday afternoon as severe thunderstorms raged across Ontario.Hundreds of high school students at a track meet in North Bay, about 330 kilometres north of Toronto, watched the funnel cloud churn across the sky.No one was injured.The only reported damage was at a steel fabrication plant just north of the city. The tornado ripped a sector of the plant's steel rood, tore off a door and smashed an office window. Heavy debris was blown as far as 1.5 kilometres away.Numerous trees were also damanged, utility poles snapped and billboards damaged.The cloud moved southeast before dissipating in the upper Ottawa valley.Residents of Barrie were especially nervous during the storm. It was exactly 17 years ago that a tornado killed 12 people in the area, eight in the city of Barrie alone.